Couple Used Brain Scans, 20,000-Mile Trip to Test Their Marriage

Motorcycle love

Newlyweds Mike and Alanna Clear decided to put their love to the ultimate test by embarking on a 20,000-mile motorcycle ride from Alaska to Argentina. The couple is shown here in their matching suits next to their refurbished Russian motorbike, a Ural Tourist-T, and sidecar in Fairbanks, Alaska. It's the furthest north they made it on their trip.

Courtesy Mike and Alanna Clear

Motorcycle love

Newlyweds Mike and Alanna Clear decided to put their love to the ultimate test by embarking on a 20,000-mile motorcycle ride from Alaska to Argentina. The couple is shown here in their matching suits next to their refurbished Russian motorbike, a Ural Tourist-T, and sidecar in Fairbanks, Alaska. It's the furthest north they made it on their trip.

Courtesy Mike and Alanna Clear

Motorcycle love

Before they left, the Clears decided to have their brains scanned to see how deeply in love they were with each other before and after the long ride. Mike Clear suffers from claustrophobia and is shown here preparing himself to go into the MRI machine for the first time. He wore a cap to cover his hair so he could see images of his wife projected inside the machine.

Courtesy Mike and Alanna Clear

Motorcycle love

Along the way, the Clears interviewed various couples to ask for their advice on what makes a happy and successful marriage. The first couple they talked to was Dennis and Nina, Russian "old believers" who lived in a remote village on the Kenai Peninsula, 200 miles south of Anchorage, Alaska. "Old believers" wear traditional Russian clothes and try to preserve Russian culture.

Courtesy Mike and Alanna Clear

Motorcycle love

"We dramatically underestimated the distances we needed to cover and didn't make it to the Canadian border and had to camp," Alanna Clear said, explaining why she and her husband stopped in Chicken, Alaska. "We also underestimated the cold. Mike stuffed newspaper and foam into my jacket while I sat in a sleeping bag."

Courtesy Mike and Alanna Clear

Motorcycle love

When they reached Utah's Valley of the Gods, the trip almost came to an abrupt halt when Mike accidently drove the bike off the road and into a ditch. "I was talking to him about having a baby over the microphone and he lost concentration in a moment of pure terror," Alanna Clear said.

Courtesy Mike and Alanna Clear

Motorcycle love

When the Clears passed through Arizona, they stopped at a Hopi Indian reservation and watched the vibrant Butterfly Festival. Over 200 members of the village donned traditional clothing to celebrate the harvest. With bells and singing, the parade worked its way through the settlement to beckon the gods for a fruitful harvest.

Courtesy Mike and Alanna Clear

Motorcycle love

The couple's relationship was tested through several hardships throughout their long journey. Aside from fights over directions, the Clears also found themselves in the heart of tropical rain season as they got into Central America. Alanna Clear said the sidecar would "fill up like a bathtub." After days of driving and sitting in the dampness, the couple loaded the bike onto a plane in Panama and headed to higher, drier Bogota, Colombia.

Courtesy Mike and Alanna Clear

Motorcycle love

Problems for the Clears continued into South America. La Paz, Bolivia is the highest capital city in the world, built in a crater. The city's extreme altitude and steep hills put a strain on their motorbike. The clutch eventually burned out and they had to wait a month for new parts to arrive.

Courtesy Mike and Alanna Clear

Motorcycle love

End of the road: Ruta 3, Argentina. The Clears stopped to take this photo in front of a sign located in the Parque Nacional Tierra del Fuego. They sold their motorbike here and eventually headed back to the United States for a second set of brain scans to see if their love survived the adventure. Find out the results and watch the Clears' full story on "<a href="http://abcnews.go.com/Nightline/Prime/">Secrets of Your Mind</a>" airing at 10 p.m. ET on Aug. 19, 2010. For more on the Clears' 20,000-mile journey, <a href="http://www.goingthedistance.org.uk">visit their website</a>.